Polyolefins are of great interest in industry as they have many uses in many different areas. For example, polyolefins, such as polyethylene and polypropylene, are often used in everything from waxes and plasticizers to films and structural components. Of late many have been interested in modifying the architecture of such polyolefins in the hopes of obtaining new and better combinations of properties. One method of controlling polyolefin architecture is to select monomers that will impart specific characteristics or tailoring the monomers used. For example, several have tried to produce large “monomers” called “macromonomers” or “macromers” having amounts of vinyl, vinylidene or vinylene termination that can be polymerized with smaller olefins such as ethylene or propylene to impart long chain branching, structural properties, etc. to a polyolefin. Typically, vinyl macromonomers are found more useful or easier to use than vinylene or vinylidene macromonomers. Examples of methods to produce various vinyl terminated macromonomers are disclosed in U.S. Pat. Nos. 6,117,962; and 6,555,635; Small, Brookhart, Bennett, J Am Chem Soc 120, 1998, 4049; and Britovsek, et al. Chem. Comm. 1998, 849; Su, et al. Organomet. 25, 2006, 666. See also B. L. Small and M. Brookhart, “Polymerization of Propylene by a New Generation of Iron Catalysts: Mechanisms of Chain Initiation, Propagation, and Termination” Macromol. 32 1999, 2322; “Metallocene-Based Branch-Block Thermoplastic Elastomers”, E. J. Markel, W. Weng, A. J. Peacock, and A. H. Dekmezian, Macromol. 33 2000, 8541-8548; and A. E. Cheman, E. B. Lobkovski, and G. W. Coates, Macromol 38 2005, 6259-6268.
Others have tried processes that produce a macromonomer then polymerize it with another smaller olefin, such as ethylene or propylene. Examples include U.S. Pat. No. 6,573,350, US 2004-0138392 A1, US 2004-0127614 A1, U.S. Pat. No. 7,223,822, and Lutz et al, Polymer 47, 2006, 1063-1072. Similar examples of macromonomer re-insertion type polymerizations include U.S. Pat. No. 6,225,432 and T. Shiono, et al. Macromolecules 32, 1999, 3723. Typically these polymerizations result in a rather low amount of the macromonomer being inserted into the growing polymer chain. For example, Shiono et al. report incorporating up to 3.8 mol % of atactic polypropylene macromonomer (Mn 630) in isotactic polypropylene having Mn of approximately 213,000.
Others have suggested in-situ variations where the macromonomer is produced in the same reactor that the polymerization occurs in, such that the macromonomer is consumed as it is produced. Examples include U.S. Pat. No. 7,294,681, US 2004-0127614, and U.S. Pat. No. 7,223,822, as well as tandem polymerization catalysts such as discussed by Bazan and coworkers (Chemical Rev 2005, 105, 1001-1020 and references therein). In many cases, long chain branched polyolefins can be produced in-situ under conditions that favor macromonomer production and its consumption in subsequently growing chains (See Chemical Rev 2005, 105, 1001-1020 and references therein).
In other areas, low molecular weight polymers and oligomers of larger monomers (typically referred to as polyalphaolefins), such as octene, decene and dodecene, have been made for uses in lubricants and additives. For examples please see WO 2007/011459 A1 and U.S. Pat. No. 6,706,828. Others have made various polyalphaolefins, such as polydecene, using various metallocene catalysts not typically known to produce polymers or oligomers with any specific tacticity. Examples include WO 96/23751, EP 0 613 873, U.S. Pat. Nos. 5,688,887, and 6,043,401, US 2003/0055184, U.S. Pat. Nos. 6,548,724, 5,087,788, 6,414,090, 6,414,091, 4,704,491, 6,133,209, and 6,713,438. Many of these polyalphaolefin molecules have terminal unsaturation that is typically hydrogenated or functionalized prior to use as a lubricant or fuel additive.
Others (VanderHart, et al. Macromol. Chem. Phys. 2004, 205, 1877-1885) have made poly(1-octadecene) using titanium tetrachloride supported on magnesium dichloride activated by triethylaluminum. Specifically, VanderHart et al. homopolymerize C18H36 (Mw=252.3; MWD 1.0) to obtain product having a broad composition distribution.
Others have focused on making comb polymers through anionic polymerization. The comb polymers can be made into model comb polyolefins through hydrogenation. See Hadjichristidis, Lohse et al (see Anionic homo- and copolymerization of styrenic triple-tailed polybutadiene macromonomers Nikopoulou A, Iatrou H, Lohse D J, Hadjichristidis N Journal of Polymer Science Part A—Polymer Chemistry 45 (16): 3513-3523 Aug. 15, 2007; and “Linear Rheology of Comb Polymers with Star-like Backbones: Melts and Solutions”, Rheologica Acta, 2006, vol. 46, no. 2, pp. 273-286.)
Likewise, J. F. Lahitte, et al. Homopolymerization of Allyl or Undecenyl Polystyrene Macromonomers via Coordination Polymerization Catalyst System, Polym. Preprint, ACS, Div. Polym. Chem. 2003 44(2) 46-47, disclose polystyryl macromonomers that produce glassy products.
Others (Lahitte, et al. Macromol Rap Comm. 25, 2004, 1010-1014) have made polymers of vinyl terminated polystyrene-containing macromonomers using cyclopentadienyl titanium trifluoride in combination with methylalumoxane in toluene at 50° C. See also Lutz, et al. Polymer, 47, 2006, 1063-1072 where macromomers of ω-allyl polystyrene, ω-undecenyl polystyrene or α,ω-undecenyl polystyrene were polymerized with ethylene using a coordination catalyst. The macromomers were incorporated into the olefin chains at levels of about 2.1 to 15.6 wt %.
Additional references of interest include: Chen, et al. JPS, Part B Polym. Phys. 38, 2965-2975 (2000); Schulze, et al. Macromolecules, 2003, 36, 4719-4726; Ciolino, et al. Journal of Polymer Science: Part A: Polymer Chemistry, Vol. 42, 2462-2473 (2001); Djalali, et al. Macromol. Rapid. Commun 20, 444-449 (1999); U.S. Pat. No. 6,197,910; WO 93/21242; and WO 93/12151.